package com.lyms.etl.datasource;

import com.lyms.etl.util.ReflectUtil;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;

/**
 * 动态切换数据源aop
 * @Author: litao
 * @Date: 2017/5/17 0017 10:48
 * @Version: V1.0
 */
@Aspect
@Component
//@Order(1) /** 保证在方法执行前执行 */
public class DynamicDataSourceAspect {
    private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceAspect.class);

    @Pointcut("@within(DynamicDataSourceAnno) || @annotation(DynamicDataSourceAnno)")
    private void advice() {
    }

    @Before("advice()")
    public void setDataSource(JoinPoint point) {
       try {
           Class<?> clazz = point.getTarget().getClass();
           MethodSignature signature = (MethodSignature) point.getSignature();
           Method method = signature.getMethod();

           /** 可能是通过接口调用方法 所以通过反射获取实现类方法上面的注解 */
           DynamicDataSourceAnno anno = ReflectUtil.getMethodAnno(clazz, method.getName(), DynamicDataSourceAnno.class);
           if(anno == null) { /** 方法上沒注解获取类上面的注解 由于只拦截了类和方法上的注解 所以不可能为空 */
               anno = clazz.getAnnotation(DynamicDataSourceAnno.class);
           }

           String datasource = anno.value();
           if(DynamicDataSourceContextHolder.containsDataSource(datasource)) {
               DynamicDataSourceContextHolder.setDataSourceType(datasource);
               logger.info("切换到 [{}] 数据源", datasource);
           } else {
               logger.info("数据源 [{}] 未找到，使用默认数据源", datasource);
           }
       } catch (Exception e) {
            logger.error("切换数据源失败: ", e.fillInStackTrace());
       }
    }
}